As TMI’s field tech I would say 80% of the pump rooms I enter have shutoff valves that are unlabeled. I have also seen in a vast number of these pump rooms, pool operators turning valves with no idea how it could be affecting the overall safety and interaction of the vital pieces of equipment in their pump room. In some cases, creating differential pressures could cause serious damage to that equipment or the plumbing itself. In one recent example, an operator closed a valve without shutting off the pump. Luckily someone noticed that the pump was still operational; had no one noticed, equipment could very well have been destroyed.
It is also important to understand the flow patterns within the plumbing and equipment in your pump room and to label all valves, shutoff valves, and equipment. Posting a laminated sequencing list in an easy to view area within the pump room is also recommended. Another scenario that I’ve witnessed was when an operator did not turn a multiport valve to the correct setting, incidentally backwashing the entire filter waste into the pool instead of the waste line. This occurred because the operator did not know which setting was the correct setting on the valve.
Understanding how and why certain valves need to be open and closed and in the correct sequence and time frame will help eliminate possible damage to your plumbing and equipment and in a worst case scenario eliminate possible injury to an employee.